One of the things that we ask straight up when we start talking with clients is – how much time each day you spend outside in the sun?
This is even more the case when we are:
- Talking with clients who live in a place that is located more toward the northern or southern extreme in terms of latitudes and therefore experiences much shorter days during winter.
- Talking with clients who have a job that requires them to be indoors through the majority of the available daylight hours.
As we’ve mentioned before on this website, we evolved to live by the light & dark cycle of the sun.
Today we’re going to talk a little more about some of the ways that exposing yourself to sunlight each day can improve your sleep.
Reason 1 – Sunlight During The Day Helps Strength The Transition Signal At Night
We’ve previously talked about how sunlight is used by your master clock as the cue for when certain hormones such as melatonin and cortisol are released.
When light turns to dark your brain stops making cortisol and starts producing melatonin. Then in the morning when the sun comes up the reverse happens.
But in a world full of artificial light your brain can easily become confused about exactly when it should be producing what.
To explain more fully it’s probably useful to understand the different levels of light intensity we’re exposed to.
Lux – A Measurement of Light Intensity
When we talk about the intensity of light, we use lux as the unit of measurement.
When you spend much of your day inside (at home or working in an office for example), you’re generally in an environment where the lighting is relatively dim, depending on exactly what you’re doing.
As a rough guide, the light in a modern office could be anywhere in the 300 – 1000 lux range and a little higher (maybe around 2000 – 3000) if you’re sitting close to a window.
Your home could be anywhere between 300 – 3,000 lux depending on the amount of natural sunlight that comes in
By comparison, when you step outside in the morning the brightness of the light will likely be in the 5,000 – 10,000 lux range on a clear morning.
And middle of the day light has an intensity of up to 100,000 lux.
But because of the way the eye works, the light outside doesn’t seem to be as much as 100 times as intense as the light inside your house or an office.
Therefore you don’t really register how much more light your eyes are exposed to when you’re outside vs. inside.
So why is this relevant?
Well you see, the brain uses the change in light intensity to help it figure out when light has turned to dark.
One process in particular is important here – Dim Light Melatonin Onset.
Your brain won’t start making melatonin until it perceives the light to have sufficiently ‘dimmed’, signalling night time has arrived.
If you don’t get any natural sunlight during the day and simply move from your house to work and back to your home again, then it’s possible that your eyes aren’t exposed to light any more intense than 2000 lux or even less.
Then at night before bed you might be sitting in your home with lights on, staring at devices and/or your television.
So the intensity of the light you’re exposed to at night will be very similar to what you’ve been exposed to during the day.
This confuses the signalling to your brain and makes it hard for the brain to know when it’s time to start shutting down for the night.
On the other hand, if you manage to spend 30 minutes outside in natural sunlight it becomes much easier for the brain to recognize when light has turned to dark, even with the artificial light around your home.
So exposing yourself to sunlight during the day strengthens the signaling to the brain to start preparing your body for sleep.
Reason 2 – Sunlight Can Increase Melatonin Production
We’ve already talked about how sunlight can help make it easier for your brain to know when it’s time to start producing melatonin in readiness for bed time.
But studies have also shown that getting out into the sun has an impact on the amount of melatonin your body produces through the night.
And the more melatonin you produce through the night the better it is for your overall sleep quality.
Reason 3 – Sunlight Increases Levels Of Serotonin & Vitamin D3
Both serotonin and vitamin D3 are important ingredients that are used for the production of melatonin.
So the fact that sunlight helps increase the availability of these ingredients goes a long way to explaining why exposure to sunlight results in a greater production of melatonin as was mentioned above.
Aside from the melatonin aspect, an increase of Vitamin D3 has been studied for it’s impacts on sleep and was found to have a positive correlation i.e more vitamin D3 generally means you’re getting better sleep.
Sleep & Camping
So hopefully you now understand a little better why the sun has such a powerful influence over how well you sleep.
One example you might be able to draw upon yourself that illustrates this impact can be seen when someone who lives and works in the city spends a week or two on holidays camping.
If you’ve ever done this yourself you’ll know that you generally get some of the best sleep of your life when you’re camping.
There have actually been studies done that show how camping can help insomniacs get better sleep.
This is in large part because the insomniac is able to reset their circadian timing and establish a much better sleep routine than when they’re at home.
When you go camping you spend your days and nights in much better synchronization with the natural rise and fall of the sun.
It’s as close as we come to living like our ancestors did and the benefits to our sleep are obvious.
There is also a potential reduction in stress that comes with camping which makes sleep easier to come by. But the exposure to natural light/dark patterns has a massive impact.
So if you haven’t been doing it already, make sure you’re getting yourself out into the sun for at least 20 – 30 minutes on a daily basis.
And remember that we’re talking direct sunlight here – not filtered through sunglasses..
Do this each day consistently and over time you’ll find it has a powerful benefit for your sleep and for the consistency of your circadian timing.